1. Field of Invention
The present invention relates to a keypad and a manufacturing method thereof. In particular, it relates to a keypad having a high degree of metallic three-dimensionality and a solid touch, and a manufacturing method thereof.
2. Description of Related Art
In today's explosive growth of information technology, electronic devices are having significant impact upon people's lives, especially in portable electronic devices, for example, cellular phone, personal digital assistant, and others. For gaining consumer acceptance, the exterior design for portable electronic device is continuously developing. Although the consumers often consider prices and functionalities during the purchase of portable devices, nevertheless, more and more are focused on the exterior design, thus allowing the exterior design of portable electronic devices to evolve from the original boring rectangular shape slowly into the curved or other different new shapes. For the application in the designs of portable electronic devices, various different designs of keypads have entered the market. However, apart from design considerations, the perception of quality of the keypad is another main criterion for consideration. Typically speaking, although the exterior appearance can be embellished after the plastic keypad undergoes color spray painting, laser engraving, and other processing operations, nevertheless, the effect of metallic luster cannot be achieved.
There is a manufacturing method for a conventional keypad for manufacturing keypad having the effect of metallic luster. FIG. 1A to FIG. 1D illustrate the cross-sectional views of the manufacturing process flow of a conventional keypad. Referring to FIG. 1A, a plastic sheet 110 is first provided in the manufacturing method for a conventional keypad. The plastic sheet 110 has a first surface 112 and a second surface 114, in which a plurality of touchpads 116 which are independently operated are formed on the plastic sheet 110.
Referring to FIG. 1B, a decorative layer 120 is formed on the first surface 112 of the plastic sheet 110. The method for forming the decorative layer 120 is, for example, the deposition of a metal layer using electroplating, spraying of a layer of silver paint, or printing of a material layer having metallic luster using a printing method.
Referring to FIG. 1C, the patterns on the decorative layer 120 are formed by conducting laser engraving or etching fabrication process to the decorative layer 120. By means of using patterns on the decorative layer 120, patterns, numerals, or words are formed on the touchpad 116.
Referring to FIG. 1D, a protruding point layer 130 is formed afterwards on the second surface 114 of the plastic sheet 110. The protruding point layer 130 includes a plurality of protrusions 130a, and the position of every protrusion 130a corresponds to each of the touchpads 116 respectively. Therefore, a keypad 100 having metallic luster is manufactured.
However, the thickness is thinner for the aforementioned method of forming the decorative layer 120. For example, the thickness of the metal layer formed using electroplating is at most 6 microns (μm), and the thickness of the silver paint layer formed using spraying method is at most 30 microns. If the metallic 3D effects of patterns, numerals, or words are to be formed on the keypad 100, the thickness of the decorative layer 120 has to be at least 400 microns. Therefore, although the conventional keypad 100 may possess metallic luster, it is not able to produce the metallic three-dimensionality and a solid feel.